(1) Field of the Invention
This invention relates to heat transfer systems, and more particularly to an improvement in heat transfer systems of the type which are operative as heating systems for building structures.
(2) Description of the Prior Art
One of the conventional ways by which building structures have long been heated is through the use of a closed heat transfer system. In accordance therewith, some medium capable of being heated is made to flow in a closed path through the building structure. More specifically, the medium is heated by means of a suitable heat source and is thereafter circulated through the building structure. As the heated medium flows throughout the building structure it gives off its heat, and as a consequence effects a heating of the building structure. Eventually the medium, after giving off a significant amount of its heat, is caused to return to the site of the heat source whereupon the latter once again functions to effect a heating of the medium and the process heretofore described is repeated.
One type of closed heat transfer system which is often to be found employed, particularly in structures that are intended for residential or office use, is that known as a baseboard hot water heating system. Such a system commonly consists of a fluid carrying means through which water is made to circulate, circulating means operative to effect the circulation of the water, and a heat source which is operative to heat the water preparatory to its being circulated through the fluid carrying means. More specifically, the fluid carrying means, the circulating means and the heat source are operatively connected in a closed loop system. Heated water is circulated through the fluid carrying means which commonly takes the form of a system of small diameter piping. This piping, i.e., a multiplicity of interconnected pipes, furthermore is most often provided with means operative to assist in the transfer of heat from the pipes and more specifically the hot water flowing therethrough. Namely, the pipes frequently have fins, etc., operatively associated therewith. The fluid carrying means is located adjacent to the floor of the room to take advantage of the well-known fact that heat rises. Accordingly, the heat being given off by the hot water flowing in the pipes rises from the floor of the room to the ceiling thereof, and in doing so thereby effects a heating of the room.
Conventional closed loop hot water heating systems of the type described above are known to suffer from several disadvantages. For instance, the medium which is heated, commonly in a boiler by a suitable heat source, and the medium which is circulated through the fluid carrying means are normally one in the same, i.e., water. As a consequence, the mode of operation of such systems precludes the use of mediums which are more efficient as a heat sink; namely, mediums which once heated are known to retain their heat more effectively than does water. Secondly, in the course of being circulated through the closed loop heating system, the medium as it passes through the boiler for purposes of becoming heated therein naturally becomes agitated. One consequence of the medium becoming agitated is that a less efficient heating of the medium takes place. Thirdly, in such closed loop heating systems air bubbles are very frequently generated. These air bubbles are most often caused as a result of the operation of the circulating water pump. Frequently the effect of such air bubbles is to cause a disturbing movement to be present in the boiler. Disturbances other than air bubbles are also often generated as the water moves through the long lengths of pipes which the system embodies. The air bubbles and the other disturbances referred to above all function to adversely affect the efficiency of the heating system. Fourthly, such closed loop hot water heating systems are generally characterized by the fact that a significant amount of the heat being generated "goes up the stack" and thus is not being utilized to effect the heating of the structure in which the heating system is employed.
Because of increasing energy costs, there is a need to provide a closed loop hot water heating system which embodies certain features of an advantageous nature. For instance, such a heating system desirably should embody the capability of utilizing different mediums. Namely, the medium being heated in the boiler could be different from the medium being circulated in the piping. The benefit which flows from such a mode of operation is that because no exchange of fluid occurs in the boiler, the medium to be heated in the boiler is not limited to water but rather can be selected on the basis of its ability to serve as a heat sink. Secondly, in such a heating system the fluid in the boiler will stay calm or "dead" thereby obviating the above-discussed inefficiencies of prior closed loop hot water heating systems. Thirdly, the boiler in such an improved closed loop hot water heating system would be further characterized by the fact that no disturbing movement occurs in the boiler stemming from the presence therein of air bubbles.